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 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
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 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
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 *
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 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Copyright (c) 2022 Huawei Device Co., Ltd.
 *
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 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
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class PkgInt {
  ////////////////////////////////////////////////////////////////
  // constants
  ////////////////////////////////////////////////////////////////
  public static INDEX_SHIFT_4BITS:number = 3;
  public static INDEX_SHIFT_8BITS:number = 2;
  public static INDEX_SHIFT_16BITS:number = 1;

  public static SHIFT_MASK_4BITS:number = 7;
  public static SHIFT_MASK_8BITS:number = 3;
  public static SHIFT_MASK_16BITS:number = 1;

  public static BIT_SHIFT_4BITS:number = 2;
  public static BIT_SHIFT_8BITS:number = 3;
  public static BIT_SHIFT_16BITS:number = 4;

  public static UNIT_MASK_4BITS:number = 0x0000000F;
  public static UNIT_MASK_8BITS:number = 0x000000FF;
  public static UNIT_MASK_16BITS:number = 0x0000FFFF;

  ////////////////////////////////////////////////////////////////
  // fields
  ////////////////////////////////////////////////////////////////
  private indexShift:number = null;
  private shiftMask:number = null;
  private bitShift:number = null;
  private unitMask:number = null;
  private data:number[] = null;

  ////////////////////////////////////////////////////////////////
  // methods
  ////////////////////////////////////////////////////////////////
  constructor(indexShift:number,
                     shiftMask:number,
                     bitShift:number,
                     unitMask:number,
                     data:number[]) {
    this.indexShift = indexShift;
    this.shiftMask = shiftMask;
    this.bitShift = bitShift;
    this.unitMask = unitMask;
    this.data = data.copyWithin(0, 0, data.length-1);
  }

  public static pack16bits(a:number, b:number):number {
    return ((b << 16) | a);
  }

  public static pack8bits(a:number, b:number, c:number, d:number):number {
    return PkgInt.pack16bits(
      (b << 8) | a,
      (d << 8) | c
    );
  }

  public static pack4bits(a:number, b:number, c:number, d:number, e:number, f:number, g:number, h:number):number {
    return PkgInt.pack8bits(
      (b << 4) | a,
      (d << 4) | c,
      (f << 4) | e,
      (h << 4) | g
    );
  }

  public unpack(i:number):number {
    return (
      (this.data[i>>this.indexShift] >> ((i&this.shiftMask)<<this.bitShift)) & this.unitMask
    );
  }
}

export default PkgInt;